Why It Works
- A coarsely pounded paste gives the curry an assertive aromatic punch.
- Pla ra, a sauce made from fermented freshwater fish, adds intense savoriness with a hint of sweetness
- The sweetness in the pla ra is complemented by the nuttiness of toasted-rice powder.
- Cooking vegetables in stages ensures they don't overcook.
- Stirring in a generous amount of fresh dill off-heat gives the curry its signature refreshing aroma.
The cuisine of Isan, the northeastern region of Thailand that borders Laos and Cambodia, has become more popular outside of Thailand in recent years, thanks to dishes like the papaya salads known as som tum and fiery, minced-meat salads known as laab (or "larb," as you often see it written on menus and online).
These are iconic dishes and are well worth celebrating, but there are also plenty of other lesser-known but equally outstanding regional specialties that deserve attention, like this bright curry loaded with fresh herbs and vegetables, which I like to think of as the perfect chicken soup.
Unlike rich gaeng khiao waan gai or gaeng massaman neua, both of which are made with coconut milk, gaeng om gai is a much lighter, water-based curry that highlights the refreshing qualities of its components. The tender-crisp bite of cabbage, yu choy, and Thai apple eggplants; the tender pieces of chicken; the savory funk of fish sauce and pla ra, a thick, murky, fish sauce made from fermented freshwater fish; the cooling aroma and flavor of fresh dill; and the aromatic punch and chile heat of a coarsely pounded curry paste.
If you're not familiar with Thai cuisine's diversity, gaeng om may seem a little odd. Like most Isan dishes, it doesn’t offer you the familiar comforts of palm sugar or coconut milk, and in fact it's more representative of a traditional gaeng (curry) from centuries in the past. Its sauce is is a combination of three key elements: a coarsely textured aromatic paste, water or stock, and pla ra.
While nam pla, the fish sauce that has become a staple in kitchens all over the world, is made from anchovies and salt, pla ra is made from freshwater fish, khao khua (roasted-rice powder), and salt. It has a more intense funkiness than nam pla, and a subtle sweetness; even in Thailand, pla ra is considered an acquired taste.
The coarsely pounded paste is another element of the recipe that may require you to throw away preconceived notions of how Thai curries are made. Unlike the finely textured paste used in dishes like panang curry, gaeng om uses a coarsely pounded paste, similar to something you might make for a stir fry: chiles, lemongrass, garlic, shallots, and makrut lime leaves are crushed in a mortar and pestle, but just until they've release their natural oils and fragrance.
Once the paste is prepared, you fry it with the chicken pieces until it smells amazing, and then you loosen it with chicken stock and bring the sauce to a simmer. You then add vegetables in stages, to cook them through without sacrificing their crisp bite, and a healthy pinch of khao khua helps to thicken the broth while also adding some nutty, toasty notes. Finally, off-heat, you add some more makrut lime leaves, green onions, and dill; adding these elements right at the end and reducing the temperature maintains the freshness of the herbs and allows their flavors to infuse the sauce slowly, similar to making a tea.
If you want to experiment by adding other ingredients to this curry, here are a few suggestions that I think are appropriate for its flavor profile. You can switch the protein up by using pork or fish; you can use other vegetables, like pumpkin, long beans, or mushrooms. You can also use other herbs: culantro (sawtooth coriander) and sweet (a.k.a. Thai) basil work very well in the curry, as does Thai lemon basil (bai maenglak), if you can find it. (While Thai lemon basil is traditionally included in this dish, it's seasonal and hard to come by in the US, so I chose to omit it from the ingredient list.)
Once prepared, this curry pairs perfectly with Thai sticky rice.
- For the Curry Paste:
- 1/2 teaspoon Diamond Crystal kosher salt
- 2 stalks lemongrass, bottom 4 to 5 inches only, outer leaves discarded, tender core thinly sliced (about 30g sliced lemongrass)
- 3 small shallots (60g), quartered
- 3 medium garlic cloves (15g)
- 2 fresh or frozen makrut lime leaves, middle rib removed (see note)
- 5 fresh red Thai chiles (10g), stemmed
- For the Curry:
- 1 pound (450g) boneless skinless chicken thighs, cut into 1 1/2-inch pieces
- 1/2 teaspoon Diamond Crystal kosher salt
- 1 tablespoon (15ml) vegetable oil
- 3 cups (710ml) homemade chicken stock, low-sodium store-bought chicken broth, or water
- One 4-inch piece fresh galangal, sliced crosswise into 1/8-inch-thick pieces (about 2 tablespoons; 30g)
- 3 tablespoons (45ml) pla ra (Thai fermented fish sauce) (see note)
- 1 tablespoon (15ml) fish sauce
- 3 Thai apple eggplants (about 3 ½ ounces; 100g total), stemmed, quartered, and placed in a small bowl of water (see note)
- 3 1/2 ounces (100g) green cabbage, cut into 3-inch pieces (about 2 cups)
- 5 1/4 ounces (150g) yu choy, cut into 2-inch pieces (6 to 8 stalks)
- 2 tablespoons (15g) khao khua (Thai toasted-rice powder)
- 10 sprigs fresh dill (50g), woody bottom stems removed and discarded, tender stems and fronds cut into 2-inch pieces
- 5 fresh or frozen makrut lime leaves, middle rib removed (see note)
- 4 scallions (60g), cut crosswise into 1 1/2-inch pieces
- Cooked sticky or jasmine rice, for serving
For the Curry Paste: Combine salt and lemongrass in a granite mortar and pestle and pound until a coarse paste forms, about 2 minutes. Pounding thoroughly between each addition to break down and incorporate ingredients into a coarse paste (3 to 4 minutes of pounding per addition), add in the following order: shallots and garlic; Thai chiles and makrut lime leaves. It should take about 10 minutes total to pound ingredients into a coarse paste, with visible pieces of chile and makrut lime leaf.
For the Curry: Season chicken with salt; set aside. In a 3-quart saucepan, heat oil over medium heat until shimmering. Add curry paste and, using a rubber spatula, stir vigorously to combine, scraping sides of the saucepan to fully incorporate paste. Cook, stirring constantly, until fragrant, 1 to 2 minutes. Add chicken, stir to coat with paste, and cook, stirring frequently, until chicken is pale white and opaque on all sides, about 2 minutes.
Add chicken stock and galangal and bring to a rapid simmer. Cook, stirring occasionally, until chicken is cooked through and tender, about 10 minutes.
Add eggplant, pla ra (if using), and fish sauce. Continue to cook, adjusting heat as needed to maintain a rapid simmer, until eggplant is just cooked through but still have some bite to them, about 3 minutes. Add cabbage and yu choy, stir to combine, and cook until vegetables are barely tender, about 3 minutes. Remove from heat, add khao kua, dill, makrut lime leaves, and scallions. Stir until incorporated and herbs are slightly wilted.
Transfer curry to a large serving bowl or divide between individual bowls. Serve immediately with cooked sticky rice or jasmine rice.
Granite mortar and pestle, 3-quart saucepan
Pla ra is a fermented fish sauce made by fermenting freshwater fish with salt and rice bran or khao kua (toasted-rice powder). It can be found in Southeast Asian markets or online. If you cannot source pla ra, you can substitute with 3 tablespoons (45ml) fish sauce, bringing the total amount of fish sauce used in the recipe to 1/4 cup (60ml).
Thai apple eggplant, often labeled simply as “Thai eggplant,” can be found in Southeast Asian and Chinese markets, as well as online. While they differ greatly in flavor and texture, Japanese or globe eggplant can be used as a substitute in this recipe (use an equal amount by weight); cut eggplant into 2-inch pieces and proceed with the recipe as written. Once cut open, the flesh of Thai apple eggplants will quickly oxidize, so it’s a good idea to place them in water until you’re ready to add them to the curry.
Makrut lime leaves can be found at Southeast Asian and South Asian markets. If you’re lucky you will find them fresh, but it is more common to find them frozen (note that they are often sold under a different name that we avoid using, as it is a derogatory term in some contexts).
Make-Ahead and Storage
The curry paste can be made in advance and refrigerated in an airtight container, with plastic wrap pressed directly against the surface of the paste to prevent it from drying out, for up to 1 week. The finished curry is best enjoyed immediately, as the vegetables will lose their crispness over time.